[jira] [Updated] (CALCITE-4511) The distinct row count and population size for constant columns should be 1

["Liya Fan (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CALCITE-4511?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Liya Fan updated CALCITE-4511:
------------------------------
    Summary: The distinct row count and population size for constant columns should be 1  (was: The number of distinct values for constant columns should be 1)

> The distinct row count and population size for constant columns should be 1
> ---------------------------------------------------------------------------
>
>                 Key: CALCITE-4511
>                 URL: https://issues.apache.org/jira/browse/CALCITE-4511
>             Project: Calcite
>          Issue Type: Improvement
>          Components: core
>            Reporter: Liya Fan
>            Assignee: Liya Fan
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> Suppose we have a relation with 3 columns: {{(a, '1', '2')}}. The first column comes from an underlying table, while the other two columns are constants. 
> For this relation, we should have {{NDV(1) = 1}}, since column 1 is a constant, which have only one possible value (suppose the column index starts from 0).
> Similarly, we should have {{NDV(1, 2) = 1}}, since both columns are constants.
> We should also have {{NDV(0, 1) == NDV(0)}}, because the number of distinct values depends on the non-const column, which is {{a}} from the underlying table. 



--
This message was sent by Atlassian Jira
(v8.3.4#803005)